Field of the Invention
The present invention relates to a projection optical system and an object detection device.
Description of the Related Art
An object detection device that determines existence or non-existence of an object and measures a distance to the object has been known. Such an object detection device includes a projection optical system having a light source and an incident optical system that changes a light beam from the light source to irradiate the object as a detection target.
A laser radar for a vehicle has been known as one example of the object detection device. Such a laser radar detects existence or non-existence of an object in front of a traveling vehicle and measures a distance to the object.
The laser radar irradiates the object with laser light emitted from a light source through an incident optical system. The laser radar detects the light reflected or scattered by the object with a light detector to detect the existence or non-existence of the object in a desired range and to measure the distance to the object.
A laser radar capable of scanning a desired range by alternately turning on a plurality of light sources arranged in the scanning direction without having a deflector and a scanner such as a rotation mirror is taught by JP 2009-103529A as one example.